Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways, leading to wheezing, shortness of breath, and coughing. COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a virus that primarily targets the respiratory tract. For people with asthma, a major concern has been how SARS-CoV-2 infection might affect their sensitive lungs and increase the risk of severe illness.
How COVID-19 Affects the Respiratory System
SARS-CoV-2 initiates infection by using its spike protein to attach to the Angiotensin-Converting Enzyme 2 (ACE2) receptor, which acts as a doorway into human cells. ACE2 receptors are highly present on cells lining the nasal passages, windpipe, and air sacs deep within the lungs. Once inside, the virus replicates and triggers a powerful immune response resulting in widespread inflammation.
This inflammatory reaction can damage the lining of the airways and the delicate walls of the air sacs (alveoli). In severe cases, this damage leads to fluid accumulation, scarring, and stiffening of the lung tissue. The virus’s attachment to ACE2 also disrupts its normal protective function, which typically regulates inflammation and prevents lung injury. This disruption contributes to the severe inflammatory response seen in some people with COVID-19.
Asthma and the Risk of Severe COVID Outcomes
Initial concerns suggested that people with asthma faced a significantly higher risk for severe COVID-19 outcomes, such as hospitalization or death. However, widespread data indicated that mild or well-controlled asthma does not increase the risk of severe COVID-19 illness compared to the general population. While COVID-19 symptoms may trigger an asthma attack, asthma itself is not consistently found to be a major independent risk factor for severe disease.
The risk of severe outcomes is closely tied to the severity or poor control of the underlying asthma. Individuals with active or severe asthma, especially those who recently required oral corticosteroids or a hospital stay, may face a greater likelihood of hospitalization. Some studies suggest that non-allergic asthma, a less common subtype, might be associated with a higher risk of severe outcomes than allergic asthma.
This difference is likely due to varied biological mechanisms in different asthma subtypes and the anti-inflammatory effects of certain medications. Asthma severity, rather than a simple diagnosis, is the relevant factor when assessing the potential for a complicated COVID-19 course. Uncontrolled airway inflammation from any cause poses the primary threat when compounded by a serious respiratory infection like SARS-CoV-2.
Managing Asthma During a COVID-19 Infection
The most important management strategy is maintaining optimal asthma control, especially during periods of high viral circulation. This means continuing to take all prescribed controller medications, such as inhaled corticosteroids (ICS), exactly as directed, even if COVID-19 is contracted. Stopping these daily maintenance treatments without medical guidance can destabilize the airways and increase the risk of a severe asthma exacerbation.
People with asthma should adhere to their written Asthma Action Plan, which provides instructions on adjusting medication doses and when to use a rescue inhaler. It is important to monitor symptoms closely, as the cough and shortness of breath caused by COVID-19 can be confused with asthma symptoms. A new fever is a strong indicator of a viral infection and should prompt immediate self-isolation and testing.
If asthma symptoms worsen or do not respond to quick-relief medication, emergency medical attention should be sought immediately. Asthmatics should take general precautions, including getting vaccinated against SARS-CoV-2 and other respiratory viruses like influenza. Maintaining a sufficient supply of all asthma medications and avoiding known triggers, such as smoke or strong cleaning agents, helps protect the airways during an infection.